AARGON AGENCY INC unlawful collections on my credit report Las Vegas Nevada

On  Sept. 23 I was informed there was a negative entry on my credit report. I went on and checked it and found out there was a AARGON AGENCY INC on it and said I owed $703.00( which when you look at others issues with them they are all in the $700 range kinda bizarre) I was never contacted or informed that I owed anyone this. I called the number on the credit report(800-326-7118) and talked to a gentleman by the name of Israel. He told me that the balance was with HMA Hospital. I asked him where that was located because I have never heard of it and he said hold on and said oh it was with Riley Hospital first. I asked him the debt was for and he said my Step sons name and that I was also on the account. My son is 23 years old!!! I told him that if my son had a bill he is of legal age and that I never signed for him on a hospital bill. He said well if you will just pay a lowered amount we agree with he will have it off my credit report. I said NO SIR!!! I want to see documentation on this debt or you remove it from my credit report. He said that I still needed to clear it. I told him I would call him back after talking to the JAG. I hung up and called Riley Hospital and told them the account number and they say they have no records of a bill. I said well this company AARGON AGENCY INC is showing it on my account and I was informed that they only used one collection agency Advance collections and would not have given it to anyone.

I then called AARGON AGENCY INC back and they demanded that I give them personal information. I told them I was only giving them the information on my credit report (account Number and name) They said they couldn't help me then. I said then remove it from the credit report.  Then yesterday I received a litter from AARGON AGENCY INC stating that I have 30 days to dispute their records or it is going to stay on the credit report. I am in process of getting the hospital to show I do not owe it and that they did not send it to the collection agency. These people are insane!!!! I WANT IT OFF MY REPORT!!!! How can they not understand I am not responsible?? I asked for them to validate it and still nothing. Just threats that it will stay on!!! GRRRRR!!!